Method of making compressor blades



y 1956 R. G. FRIEDMAN 2,743,509

METHOD OF MAKING COMPRESSOR BLADES Filed Dec. 30, 1952 3 Sheets-Sheet l15 7 Ploanzssslvz HEA DE/Z f i g i%o j l/VDULT/ON 12 HEATER 2:,113

4 1 47%? 2/10 PROGRESSIVE 1 r HEADER IN VEN TOR. ROBERT 6. FRIEDMANEICHEX, w 7T6 06m am lvz/v/vr ATrozalvgY-s May 1, 1956 R. G. FRIEDMAN2,743,509

METHOD OF MAKING COMPRESSOR BLADES Filed Dec. 30, 1952 3 Sheets-Sheet 2IN VEN TOR. ROBE/27" 6. FRIEDMAN May 1, 1956 R. G. FRIEDMAN METHOD OFMAKING COMPRESSOR BLADES 3 Sheets-Sheet 3 Filed Dec. 30, 1952 INVENTOR.

ROBE/27' G. FEM OMAN United States Patent METHOD OF MAKING COMPRESSORBLADES Robert G. Friedman, Tiflin, Ohio, assignor to The lfla tionalMachinery Company, Tiflin, Ohio, a corporation of Ohio ApplicationDecember 30, 1952, Serial No. 328,604

2 Claims. (Cl. 29-1563) This invention relates to the forging of metalarticles having enlarged sections and more particularly to the forgingof compressor blade blanks wherein large variations in cross section arenecessary.

Great difiiculties have been encountered when attempting to forgearticles having large variations infcross section and it has beennecessary in the past to provide numerous anneals to prevent fracturesand adhesions. Difficulty has particularly been present in attempts toform compressor blade blanks, since such articles require a large rootsection and a relatively small stem.

An important object of this invention is to provide a method for forgingarticles wherein large variations in cross section are necessary.

Another object of this invention is to provide a method which combineshot and cold forging in the forming of articles having large changes incross section.

It is still another object of this invention to provide a method offorging compressor blade blanks wherein it is necessary to upset a largeroot section while mantaining a relatively small stem section.

A still further object of this invention is to provide a method offorging articles combining cold extrusion of a portion of a blank,heating of the unextruded portion, and hot upsetting of the heatedportion of the blank.

The foregoing and other objects and advantages will become apparent inview of the following description taken in conjunction with thedrawings, wherein:

Fig. l is a schematic view of the entire apparatus preferably employedin forging a compressor blade-blank according to this invention;

Fig. 2 shows the blank before working;

Fig. 2a is an end view of the blank;

Fig. 2b shows the blank after cold extrusion;

Fig. 2c is an end view of the blank of Fig. 2b;

Fig. 2d shows an extruded blank partially hot forged;

Fig. 2e is an end view of the blank of Fig. 2d;

Fig. 2 shows the completed compressor blade blank;

Fig. 23 is an end view of the blank of Fig. 2f;

Fig. 3 is a cross sectional view showing the die arrangement in thefirst header;

Fig. 4 is a schematic view of a preferred apparatus utilized fortransferring the blank from the first header to the second header; and

Fig. 5 is a cross sectional view of the die arrangement utilized in thesecond header.

In a preferred embodiment of this invention, stock is selected having across section larger than the desired cross section of the stem portionof 'the compressor blade blank and smaller than the cross section of theroot section in the finished compressor blade blank. This permits thereducing of the cross sectional area of the stock to form the stemsection of the blank and subsequently upsetting the large root sectionfrom stock having a cross section substantially larger than the crosssection of the stem section. By employing this method it is possible toreduce the amount of upsetting necessary in the formation of the rootsection.

Patented May 1, 1956 ice A method of forming compressor blade blanksaccording to this invention also utilizes the processes of hot and coldforging wherein a portion of the stock is extruded cold to form the stemsection of the finished blank after which that portion of the stockwhich is to be upset to form the root section is heated. Subsequent tothe heating, hot forging is utilized to upset the root section therebyforming the finished compressor blade blank.

If articles such as compressor blade blanks were forged by coldextruding and upsetting, it would be necessary to provide interimanneals to eliminate ruptures. Such anneals are not only time consumingbut result in more costly process. It is also unsatisfactory to use hotextrusion and upsetting since a small extrusion angle is required toprevent lines at the extrusion point which result in defects in theblades. To drive metal down the small extrusion angle requires such ahigh pressure that the hot metal which is unconfined between the dieswould be upset resulting in failure of the process. By combining coldextrusion, localized heating of the unextruded portion of the blank, andhot upsetting of the heated portion of the blank it is possible to forgearticles wherein large variations in cross section are present withoutrequiring time consuming and expensive interim anneals.

Referring to Fig. l, the first phase of the forging process takes placeat the first progressive header 10, similar to the header disclosed inthe patent to Clause No. 2,043,- 093. In the preferred embodiment ofthis invention wire stock 11 is fed into an automatic cut-off in thefirst header 10 which supplies the individual blanks that aresubsequently extruded into a first intermediate blank having a stemportion of reduced cross section. From the first progressive header 10the first intermediate blank is automatically transferred through thesecond phase of the process wherein the large section of the blank isheated by an induction heater 12. It is preferred that the conveyer belt13 utilized to transport the first intermediate blank from the firstheader 10 through the induction heater 12, and on to the second header14. At the second header the first intermediate blank is forged into thefinal compressor blade blank by upsetting the hot portion of the blank.

Referring to Fig. 3 the wire stock 11 is fed by any conventional meansthrough the bore 16 in the cut-off die 17 at the first station on theheader and on through the bore 18 in the shearing element 19 until itengages the stock feed stop 21. The stock feed stop 21 may beconstructed in any suitable manner but should be adjustable axiallyrelative to the cut-off die 17 to permit adjustment of the quantity ofmetal in the blanks. The shearing element 19 then cuts the blank 22 fromthe wire stock by moving radially along the cut-off die 17. The amountof metal necessary to form the finished compressor blade blank and thecross section of the wire stock 11 determines the length of the blank22. When forging a compressor blade blank according to this inventionthe stock 11 should be selected to have a cross sectional area largerthan the stem or smallest cross section in the finished blank butsmaller than the cross section of the root or largest cross section ofthe finished blade blank. After the blank 22 is sheared from the wirestock 11 it is positioned before the extruding die 23 at the secondstation of the header 10 as shown in Fig. 3. The transfer mechanism (notshown) may be of any conventional type and is not critical to thisinvention. The die 23 is formed with an enlarged bore portion 24 openingon the forward face of the die and a reduced bore portion 26 spaced fromthe face of the die and axially aligned with the bore 24. A transitionsection 27 is formed between the bores 24 and 26. The bore 24 is formedhaving a cross section substantially equal to the cross section of theblank 22 and the bore 26 is formed having a cross section substantiallyequal to the cross section desired in the finished stem'of thecompressor blade blank. The die breast 28 in which the extruding die 23is mounted is provided with a bore 29 axially aligned with the bore 26in the die 23. A reciprocating die 31 is mounted on the header slide(not shown) and is formed with a receiving bore 32 axially aligned andsubstantially equal in cross section to the bore 24 in the extruding die23. A backing pin 33 is mounted within the bore 32 with a forward face34 spaced from the forward end of the reciprocating die 31. As theheader slide moves forward the blank 22 enters the bore 24 until itengages the transition section 27 and enters the bore 32 until itengages the face 34 of the pin 33. As the header slide continues to movetoward the die breast 28 the blank 22 is extruded through the bore 26forming the first intermediate blank 36 having a stem portion 37 ofreduced cross section and a base section 38 having a cross sectionsubstantially equal to the cross section of the blank 22.

In the preferred embodiment the stem portion 37 of the firstintermediate blank 36 is formed with a cross section equal to thedesired cross section of the stem portion of the finished compressorblade blank.

As the header slide moves away from the die breast 28 the ejector pin 39ejects the first intermediate blank 36 from the die 23 and the firstintermediate blank is positioned by the transfer mechanism (not shown)in front of the holding die 41 at the third station in the header 10.

It should be noted that no forging takes place at the die 41 and thisstation is used to maintain control of the first intermediate blank 36.The punch 42 is mounted on the header slide of the header and moves thefirst intermediate blank into the bore 43 in the die 41. The ejector pin44 is axially slidable in the bore 43 and ejects the blank from the borewhen the punch 42 moves axially away from the die 41. The firstintermediate blank 36 is then transferred by any conventional means tothe conveyer belt 13 shown in Fig. 4. The transfer mechanism fortransferring the first intermediate blank to the conveyer belt 13 mayinclude a tube or slide 46. The particular conveyer belt shown in Fig. 4is synchronized with the operation of the first header 14 and is adaptedto receive the stern portion 37 of the first intermediate blank 36. Thebase section 38 of the first intermediate blank 36 is arranged to extendlaterally relative to the conveyer belt 13.

The heater 12 is of the induction type and is arranged with an inductioncoil 47 arranged to surround the base section 38 as the firstintermediate blank is moved from the first header to the second header.Since only the base section 38 of the blank is surrounded by theinduction heating coil 47 only that portion of the blank is heated bythe induction heater and the stem portion remains relatively cool. Aninduction heating coil is particularly well adapted to this processsince it makes possible to rapidly heat a portion of the blank. When theintermediate blank reaches the slide 48 it is ejected from the conveyerbelt 13 by any conventional method such as an air blast or ejector pin.The intermediate blank then slides down the slide 48 until it isreceived by a conventional type transfer mechanism (not shown)positioned for the second forging operation at the first station in thesecond header.

It is preferable to synchronize the operations of the first and secondheader as well as the conveyer belt so that control of the blank ismaintained during the entire process to reduce the handling necessary.

Referring to Fig. 5, the first intermediate blank is aligned with thedie 51 mounted in the die breast at the first station of the secondheader 14. The die 51 is formed with a bore 52 which is substantiallyequal in cross section to the cross section of the stem 37. The forwardend of the bore 52 is rounded as at 53 to facilitate the upsetting ofthe root or enlarged section of the sec 0nd intermediate blank 54. Thereciprocating die 56 is mounted on the header slide of the second header14 and is formed with a bore 57 axially aligned with the bore 52. Thebore 57 is formed having a cross sectional area substantially equal tothe cross sectional area of the base section 38 and is tapered as at 58to an enlarged mouth section having a size substantially equal to themouth section of the die 51. The backing pin 59. is mounted in the bore57 with its forward face 61 spaced from the mouth of the die 56. Anejector pin 62 is mounted within the bore 52 of the die 51 with itsforward face 63 spaced from the mouth of the die 51. The length of thebore 52 between the face 63 and the rounded section 53 is substantiallyequal to the length of the stem 37 on the first intermediate blank 36.As the header slide moves the die 56 toward the die 51 the stem portion37 of the first intermediate blank 36 slides into the bore 52 in the die51 until the end of the blank engages the forward face 63 of the ejectorpin 61. At the same time the base section 38 of the first intermediateblank slides into the bore 57 until the end engages the forward face 61of the backing pin 59. As the header slide continues to move thereciprocating die 56 toward the die 51 the base section 38 of the firstintermediate blank is upset so as to fill the dies as shown in station 1of Fig. 5. Since the stem 37 of the blank is relatively cool and thebase section 38 is heated the upsetting of the enlarged section 64 ofthe second intermediate blank 54 does not result in any upsetting of thestem section. As the header slide moves away from the die breast theejector pin 62 ejects the second intermediate blank 54 into transferfingers (not shown) which position the blank at the second station ofthe second header 14.

The die 66 is mounted in the die breast at the second station of thesecond header 14 and is formed with a bore 67 having a cross sectionequal to the cross section of the stem of the finished compressor bladeblank. At the forward end of the die 66 the bore is flared at as 68. Thedie 69 is mounted in the header slide of the second header 14 and isformed with a bore 71 having a cross section substantially equal to thecross section of the bore 57 in the die 56. The forward end of the bore71 in the die 69 is flared as at 72. The flare 68 and the flare 72 aresubstantially similar so that the mouth size of the two dies 66 and 69is equal. A backing pin 73 is mounted in the bore 71 with its forwardface 74 spaced from the forward end of the die 69. An ejector pin 76 ismounted in the bore 67 of the die 66 with its forward face 77 spacedfrom the forward end of the die 66. As the header slide moves forwardtoward the die breast the stem of the second intermediate blank movesinto the bore 67 until its end engages the forward face 77 of theejector pin 76. At the same time the other end of the secondintermediate blank moves into the bore 71 until it engages the forwardface 74 of the backing pin 73. As the header slide continues to movetoward the die 66 the root section 78 of the finished compressor bladeblank 79 is upset thereby forming the finished compressor blade blank79. Again, since the stem section of the second intermediate blank isrelatively cool and since the large section 64 is relatively hot a largeamount of upsetting may be accomplished at the root section 78 withoutthe use of excessive pressures. As the header slide moves away from thedie breast the finished compressor blade blank 79 is ejected by theejector pin 76 thereby completing the process of forming the compressorblade blank.

Since the bore 57 in the die 56 and the bore 71 in the die 69 have across sectional area substantially equal to the area of the base sectionof the blank, a portion of the heated end of the blank is confinedthereby preventing this portion of the blank from upsetting. Thisstructure permits the upsetting of a portion of the blank spaced fromthe ends.

By combining the steps of reducing the cross section from stock of alarger size than the cross section desired in the stem 81 of thefinished compressor blade blank, it is possible to forge an articlewherein relatively large variations in cross section are present. Bycombining this method with the hot upsetting of the large root sectionsmakes possible even larger variations in the cross section of thefinished article.

It should be understood that although the forging method according tothis invention, though particularly adapted to the formation ofcompressor blade blanks, is equally well adapted to the forging of otherarticles wherein large variations in cross section are desired.

Having completed a detailed description of a preferred embodiment of thepresent invention so that others skilled in the art may be able tounderstand and practice the same, I state that what I desire to secureby Letters Patent is not limited by said preferred embodiment but ratheris defined in what is claimed.

I claim:

1. A method of extruding and forging elongated metal blanks having astem portion of one cross section and a root section spaced therefrom oflarger cross section comprising, the steps of extruding said sternportion of small cross section from a blank having substantial uniformcross section larger than said stern cross section and smaller than saidlarge root portion, conveying said extruded blank so that the unextrudedportion of the blank extends laterally from a conveyor, heating theentire unextruded portion of the blank as the conveyor moves theunextruded portion of the blank through a heating device, confining theextreme end of the heated unextruded portion of the blank in a diecorresponding to the diameter of the unextruded portion, confining theextruded stern portion in a die corresponding to the extruded stemdiameter, and exerting pressure longitudinally on said heated confinedunextruded portion of the blank, whereby the heated unconfined portionof the unextruded portion is upset by the pressure to provide theenlarged upset root portion.

2. A method of extruding and forging elongated metal blanks having astern portion of one cross section and a root section spaced therefromof larger cross section comprising, the steps of extruding said stemportion of small cross section from a blank having substantial uniformcross section larger than said stem section and smaller than large rootsection, inserting the extruding stern portion of the blankssuccessively into spaced holders of a conveyor, leaving the unextrudedstem portions projecting therefrom, conveying the extruded blanksthrough a heating zone to heat the entire unextruded portion of theblank, confining the extreme end of the heated unextruded portion of theblank in a die corresponding to the diameter of the unextruded portion,confining the extruded stem portions in a die correspoding to theunextruded stem diameter, and exerting pressure longitudinally on saidheated confined unextruded portion of the blank, whereby the heatedunconfined portion of the unextruded portion is upset by the pressure toprovide the enlarged upset root portions.

References Cited in the file of this patent UNITED STATES PATENTS1,430,399 Parsons et al. Sept. 26, 1922 1,668,442 Wineman May 1, 19281,803,803 Kaufman May 5, 1931 2,473,245 Hanna June 14, 1949 2,638,663Bartlett et a1 May 19, 1953

